These studies will evaluate the chronic toxicity and carcinogenic potential of 2,2-bis(bromomethyl)-1,3-propanediol (BMP) by administering the compound in the diet to F344 rats and B6C3F1 mice at three dose levels. An interim sacrifice of 10 animals/dose group was performed with both rats and mice after 12 months of chemical exposure. This study also includes a stop study in which additional male rats (including a control group) were exposed to BMP for 3 months and then held without further treatment until the end of the study. To monitor progress of chemically-induced lesions, interim sacrifices will be conducted with the stop study animals at 3, 6, 12, and 18 months.